Development of large multielectrode arrays for epiretinal stimulation - feasibility of implantation procedures

Abstract

Purpose: To demonstrate the feasibility of implantation surgery of Very Large Retinal Stimulation arrays (VLARS) to provide artificial vision with enlarged visual fields.

Methods: Polyimide foils with a star-shaped pattern and a diameter of 12.5 mm have been fabricated for implantation. Each foil carries 244 gold electrodes divided into 63 electrodes for central and 181 electrodes for peripheral stimulation of the retinal surface. Openings for tack fixation were embedded paracentrally and into each arm of the star-shaped electrode array. Implantation was performed in pigs’ eyes including lens removal, vitrectomy and the implantation via corneal incision.

Results: Following lens removal by phacoemulsification and three-port vitrectomy, a decaline bubble was installed into the vitreous cavity. Via a corneal incision the folded stimulator was inserted into the eyeball, pushed through a posterior capsulotomy and positioned onto the decaline bubble. While the stimulator showed a good overall contact to the retinal surface after removal of the decaline bubble, implantation was finished by fixation using retinal tacks.

Conclusions: Our experiments demonstrated the feasibility of implantation surgery of large electrode arrays. Long term implantation for biocompatibility testing as well as stimulation experiments for the generation of cortical activation in animal experiments will follow.

Keywords: 696 retinal degenerations: hereditary • 762 vitreoretinal surgery